This disambiguation page lists articles associated with the title UPD. If an internal link led you here, you may wish to change the link to point directly to the intended article.
Chronic smokers often have difficulty breathing because they develop Chronic Obstructive Pulmonary Disorder, or COPD. The two diseases that fall under that category are emphys â¦ ema and chronic bronchitis.
Asthmatics (people suffering from asthma) often complain of thick and viscous mucus. This is because when you have asthma; excess mucus is produced, blocking the airways. This causes breathing to become difficult as your airways become clogged due to the decrease in mucus drainage. Mucus is functional in coating the organ membranes, preventing pollutants from invading and irritating the organs.